The research is designed to examine the formation, structure and function of plasma high density lipoproteins. This involves study of lipid-protein interactions in HDL and in HDL modified in vitro by interaction with phospholipids and apoproteins. We are studying the interaction of unilamellar vesicles of phosphatidylcholine and cholesterol/phosphatidylcholine. The resulting phospholipid-enriched lipoproteins are being analyzed by density gradient ultracentrifugation, electron microscopy, scanning calorimetry and spectroscopic techniques. We are also investigating the metabolic fate of phosphatidylcholine and cholesterol/phosphatidylcholine vesicles following injection into rats.